Although bass viols superficially resemble cellos, viols are different in numerous respects from instruments of the violin family: the viol family has flat rather than curved backs, sloped rather than squarely rounded shoulders, c holes rather than f holes, and five to seven rather than four strings; some of the many additional differences are tuning strategy (in fourths with a third in the middle—exactly like a lute—rather than in fifths), the presence of frets, and underhand rather than overhand bow grip.[9]

All members of the viol family are played upright between the legs like a modern cello, hence the Italian name viola da gamba (lit. viol of the leg). This distinguishes the viol from the modern violin family, the viola da braccio (lit. viol of the arm). A player of the viol is commonly known as a gambist.

Detail from a painting by Jan Verkolje, Dutch, c. 1674, Elegant Couple (A Musical Interlude). The theme is similar to the classic Music Lesson genre, and features a bass viol, virginal, and cittern (in the woman's hand, out of frame in this detail; see full image). This image highlights the domestic amateur class of viol players.

Vihuelists began playing their flat-edged instruments with a bow in the second half of the 15th century. Within two or three decades, this led to the evolution of an entirely new and dedicated bowed string instrument that retained many of the features of the original plucked vihuela: a flat back, sharp waist-cuts, frets, thin ribs (initially), and an identical tuning—hence its original name, vihuela de arco; arco is Spanish for "bow". An influence in the playing posture has been credited to the example of Moorish rabab players.[5] The viol is unrelated to the much older Hebrew stringed instrument called a viol (literally, "skin"). This ancient harp-like instrument was similar to the kinnor or nabla.[10][11]

Stefano Pio argues that a re-examination of documents in the light of newly collected data indicates an origin different from the vihuela de arco from Aragon:according to Pio the viol (viola da gamba) had its origins and evolved independently in Venice.[6] According to Pio, it is implausible that the vihuela de arco, which possibly arrived in Rome and Naples after 1483-1487, since Johannes Tinctoris does not mention it prior to this time, underwent such a rapid evolution by Italian instrument makers – not Venetian (circumstances specifically excluded by Lorenzo da Pavia), nor Mantuan or Ferrarese (as evidenced by Isabella and Alfonso I d' Este's orders from luthiers from other cities) – so that a ten-year span witnessed the birth and diffusion in Italy of a new family of instruments (viole da gamba or viols) which comprised instruments of different size, some as large as the famous violoni as ‘big as a man’ mentioned by Prospero Bernardino in 1493.

Pio also notes that both in the manuscript of the early 15th-century music theorist Antonius de Leno and in the treatises of the Venetian Silvestro Ganassi dal Fontego and Giovanni Maria Lanfranco (de), the fifth string of the viola da gamba is uniquely called a bordone (drone), although it is not actually a drone and is played the same as the other strings. Pio argues that this inconsistency is justifiable only assuming the invention, during the last part of the fifteenth century, of a larger instrument derived from the medieval violetta, to which were gradually added other strings to allow a greater extension to the low register that resulted from its increased size. The fifth string, already present in some specimens of these violette as a drone (bordone), was incorporated into the neck when they were expanded in size. This was then surpassed by a sixth string, named basso, which fixed the lower sound produced by the instrument. In Pio's view, the origin of the viola da gamba is tied to the evolution of the smaller the medieval violetta or vielle, that was originally fitted with a fifth string drone, where the name remained unchanged even though it ceased to perform this function.[citation needed][12]

Ian Woodfield, in his The Early History of the Viol, points to evidence that the viol does in fact start with the vihuela but that Italian makers of the instrument immediately began to apply their own highly developed instrument-making traditions to the early version of the instrument when it was introduced into Italy.[5]

Initially the family of viole ("viols") shared common characteristics but differed in the way they were played. The increase in the dimensions of the "viola" determined the birth of the viol and the definitive change in the manner the instrument was held, as musicians found it easier to play it vertically. The first consort of viols formed by four players was documented at the end of the fifteenth century in the courts of Mantua and Ferrara, but was also present in popular Venetian music ambience, noted at the Scuola Grande di San Marco, 1499; Venetian culture remained independent of Spanish influence and consequently unfamiliar with the instruments of those lands, such as the bowed vihuela de arco.[dubious– discuss][citation needed] Groups of viol players, generally called violoni, were established in the Venetian Scuole Grandi around 1530/40, but the highly traditional environment of these institutions suggests that these groups would have already been active in the general urban context during the previous two decades (1510-1520).[citation needed] Some of these players were known to have traveled to distant lands, including Vienna, the Duchy of Bavaria or the Kingdom of England where they were welcomed at the court of the Tudors and subsequently influenced England’s local instrumental production.

Viols most commonly had six strings, although many 16th-century instruments had five or even four strings. Viols were (and are) strung with gut strings of lower tension than on the members of the violin family, let alone the steel strings mostly used in those instruments today. Gut strings produce a sonority far different from steel, generally described as softer and sweeter. Around 1660, gut or silk core strings overspun with copper wire first became available; these were then used for the lowest-pitched bass strings on viols, and on many other string instruments as well.

Unlike members of the violin family, which are tuned in fifths, viols are usually tuned in fourths with a major third in the middle, mirroring the tuning employed on the vihuela de mano and lute during the 16th century and similar to that of the modern six-string guitar.

Early Italian tenor viola da gamba, detail from the painting St. Cecilia, by Raphael, c. 1510.

Viols were first constructed much like the vihuela de mano, with all surfaces, top, back, and sides made from flat slabs or pieces of joined wood, bent or curved as required. However, some viols, both early and later, had carved tops, similar to those more commonly associated with instruments of the violin family. The ribs or sides of early viols were usually quite shallow, reflecting more the construction of their plucked vihuela counterparts. Rib depth increased during the course of the 16th century, finally coming to resemble the greater depth of the classic 17th-century pattern.

The flat backs of most viols have a sharply angled break or canted bend in their surface close to where the neck meets the body. This serves to taper the back (and overall body depth) at its upper end to meet the back of the neck joint flush with its heel. Traditional construction uses animal glue, and internal joints are often reinforced with strips of either linen or vellum soaked in hot animal glue—a practice also employed in early plucked vihuela construction. The peg boxes of viols (which hold the tuning pegs) were typically decorated either with elaborate carved heads of animals or people or with the now familiar spiral scroll finial.

The earliest vihuelas and viols, both plucked and bowed, all had sharp cuts to their waists, similar to the profile of a modern violin. This is a key and new feature—first appearing in the mid-15th century—and from then on, it was employed on many different types of string instruments. This feature is also key in seeing and understanding the connection between the plucked and bowed versions of early vihuelas. If one were to go searching for very early viols with smooth-curved figure-eight bodies, like those found on the only slightly later plucked vihuelas and the modern guitar, they would be out of luck. By the mid-16th century, however, "guitar-shaped" viols were fairly common, and a few of them survive.

The earliest viols had flat, glued-down bridges just like their plucked counterpart vihuelas. Soon after, however, viols adopted the wider and high-arched bridge that facilitated the bowing of single strings. The earliest of viols would also have had the ends of their fretboards flat on the deck, level with or resting upon the top or sound board. Once the end of their fretboards were elevated above the top of the instrument's face, the entire top could vibrate freely. Early viols did not have sound posts, either (again reflecting their plucked vihuela siblings). This reduced damping again meant that their tops could vibrate more freely, contributing to the characteristic "humming" sound of viols; yet the absence of a sound post also resulted in a quieter and softer voice overall.

It is commonly believed[13] that C-holes (a type and shape of pierced sound port visible on the top face or belly of string instruments) are a definitive feature of viols, a feature used to distinguish viols from instruments in the violin family, which typically had F-shaped holes. This generality, however, renders an incomplete picture. The earliest viols had either large, open, round, sound holes (or even round pierced rosettes like those found on lutes and vihuelas), or they had some kind of C-holes. Viols sometimes had as many as four small C-holes—one placed in each corner of the bouts—but more commonly, they had two. The two C-holes might be placed in the upper bouts, centrally, or in the lower bouts. In the formative years, C-holes were most often placed facing each other or turned inwards.

In addition to round or C-holes, however, and as early as the first quarter of the 16th century, some viols adopted S-shaped holes, again facing inward. By the mid-16th century, S-holes morphed into the classic F-shaped holes, which were then used by viols and members of the violin family alike. By the mid- to late 16th century, the viol's C-holes facing direction was reversed, becoming outward facing. That configuration then became a standard feature of what we today call the “classic” 17th-century pattern. Yet another style of sound holes found on some viols was a pair of flame-shaped Arabesques placed left and right. The lute and vihuelalike round or oval ports or rosettes became a standard feature of German and Austrian viols and was retained to the very end. That feature or “genetic marker” was exclusively unique to viols and reminded one always of the viol's more ancient plucked vihuela roots, the "luteness" of viols.

Historians, makers, and players generally distinguish between Renaissance and Baroque viols. The latter are more heavily constructed and are fitted with a bass bar and sound post, like modern stringed instruments.

The bow is held underhand (palm up), similar to a German double bass bow grip, but away from the frog towards the balance point. The stick's curvature is generally convex as were violin bows of the period, rather than concave like a modern violin bow. The "frog" (which holds the bowhair and adjusts its tension) is also different from that of modern bows: whereas a violin bow frog has a "slide" (often made of mother of pearl), which pinches the hair and holds it flat and stationary across the frog, viol bows have an open frog that allows more movement of the hair. This facilitates a traditional playing technique where the performer uses one or two fingers of the bow hand to press the hair away from the bow stick. This dynamically increases bow hair tension to control articulation and inflection.

Gambas (as the name is often abbreviated) come in seven sizes: "pardessus de viole" (which is relatively rare, exclusively French and did not exist before the 18th century), treble (in French dessus), alto, tenor (in French taille), bass, and two sizes of contrabass (also known as a violone), the smaller one tuned an octave below the tenor (violone in G, sometimes called great bass or in French grande basse) and the larger one tuned an octave below the bass (violone in D).

Their tuning (see next section) alternates G and D instruments: pardessus in G, treble in D, tenor in G, bass in D (the seven string bass was in A), small violone in G, large violone in D. The alto, between the treble and the tenor, does not fit in this scheme. The treble has a size similar to a viola but with a deeper body; the typical bass is about the size of a cello. The pardessus and the treble were held vertically in the lap. The English made smaller basses known as division viols, and the still-smaller Lyra viol. The viola bastarda was a similar type of viol used in Italy for a virtuosic style of viol repertoire and performance. German consort basses were larger than the French instruments designed for continuo.

Those instruments were not all equally common. The typical Elizabethan consort of viols was composed of six instruments: two basses, two tenors and two trebles, or one bass, three tenors and two trebles (see Chest of viols). Thus the bass, tenor and treble were the central members of the family as far as music written specifically for viols is concerned. Besides consort playing the bass could also be used as a solo instrument (there were also smaller basses designed especially for a virtuosic solo role, see above division viol, lyra viol, viola bastarda). And the bass viol could also serve as a continuo bass. The pardessus was a French 18th century instrument that was introduced to allow ladies to play mostly violin or flute music[14] but eventually acquired its own repertoire. The alto was a relatively rare smaller version of the tenor. The violones were never part of the consort of viols but functioned as the contrabass of all kinds of instrumental combinations.

The standard tuning of the viol is in fourths, with a major third in the middle (like the standard Renaissance lute tuning). For bass viols, the notes would be (from the lowest) D-G-c-e-a-d', with an additional low AA for seven-string bass viols. For the tenor viol, the tuning is G-c-f-a-d'-g' (a smaller tenor, or "alto" viol, is usually tuned A-d-g-b-e'-a'). The treble viol is one octave higher than the bass.

Alternate tunings (called scordatura) were often employed, particularly in the solo lyra viol style of playing, which also made use of many techniques such as chords and pizzicato, not generally used in consort playing. An unusual style of pizzicato was known as a thump. Lyra viol music was also commonly written in tablature. There is a vast repertoire of this music, some by well-known composers and much by anonymous ones.

Much viol music predates the adoption of equal temperament tuning by musicians. The movable nature of the tied-on frets permits the viol player to make adjustments to the tempering of the instrument, and some players and consorts adopt meantone temperaments, which are arguably more suited to Renaissance music. Several fretting schemes involve frets that are spaced unevenly to produce "better-sounding" chords in a limited number of keys. In some of these schemes, the two strands of gut that form the fret are separated so that the player can finger a slightly sharper or flatter version of a note (for example G sharp vs. A flat) to suit different circumstances.

There were then several important treatises concerning or devoted to the viol. The first was by Silvestro Ganassi dal Fontego: Regola Rubertina & Lettione Seconda (1542/3). Diego Ortiz published Trattado de Glosas (Rome, 1553), an important book of music for the viol with both examples of ornamentation and pieces called Recercadas. In England, Christopher Simpson wrote the most important treatise, with the second edition being published in 1667 in parallel text (English and Latin). This has divisions at the back that are very worthwhile repertoire. A little later, in England, Thomas Mace wrote Musick's Monument, which deals more with the lute but has an important section on the viol. After this, the French treatises by Machy (1685), Rousseau (1687), Danoville (1687), and Etienne Loulie (1700) show further developments in playing technique.

Viols were second in popularity only to the lute (although this is disputed), and like lutes, were very often played by amateurs. Affluent homes might have a so-called chest of viols, which would contain one or more instruments of each size. Gamba ensembles, called consorts, were common in the 16th and 17th centuries, when they performed vocal music (consort songs or verse anthems) as well as that written specifically for instruments. Only the treble, tenor, and bass sizes were regular members of the viol consort, which consisted of three, four, five, or six instruments. Music for consorts was very popular in England in Elizabethan times, with composers such as William Byrd and John Dowland, and, during the reign of King Charles I, John Jenkins, William Lawes and Tobias Hume. The last music for viol consorts before their modern revival was probably written in the early 1680s by Henry Purcell.

Perhaps even more common than the pure consort of viols was the mixed or broken consort (also called Morley consort). Broken consorts combined a mixture of different instruments—a small band, essentially—usually comprising a gathering of social amateurs and typically including such instruments as a bass viol, a lute or orpharion (a wire-strung lute, metal-fretted, flat-backed, and festoon-shaped), a cittern, a treble viol (or violin, as time progressed), sometimes an early keyboard instrument (virginal, spinet, or harpsichord), and whatever other instruments or players (or singers) might be available at the moment. The single most common and ubiquitous pairing of all was always and everywhere the lute and bass viol: for centuries, the inseparable duo.

The treble viol in d and the even smaller pardessus de viole in g (often with only five strings) were also popular instruments in the 18th century, especially in France. Composers like Jean-Baptise Barrière, Georg Phillipp Telemann and Marin Marais wrote solo- and ensemble pieces for treble or pardessus. It was also common to play music for violins or flutes or unspecified top parts on small viols.

Historic viols survive in relatively great number, though very few remain in original condition. They can often be found in collections of historic musical instruments at museums and universities. Here are some of the extant historic viols at The Metropolitan Museum of Art:

Painting by Abraham Bosse, Musical Society, French,
c. 1635. Subject matter depicts amateur social music making, featuring lute, bass viol, and singers, with part books spread around the table. This is also representative of one kind of broken consort, albeit with minimal instrumentation.

Today, the viol is attracting ever more interest, particularly among amateur players. This may be due to the increased availability of reasonably priced instruments from companies using more automated production techniques, coupled with the greater accessibility of music editions. The viol is also regarded as a suitable instrument for adult learners; Percy Scholes wrote that the viol repertoire "...belongs to an age that demanded musicianship more often than virtuosity."

There are now many societies for people with an interest in the viol. The first was Viola da Gamba Society of Great Britain, which was established in the United Kingdom in 1948 and has a worldwide membership. Since then, similar societies have been organized in several other nations. In the 1970s, the now defunct Guitar and Lute Workshop in Honolulu, Hawaii generated resurgent interest in the viol and traditional luthierie methods within the western United States.

A notable youth viol group is the Gateshead Viol Ensemble. It consists of young players between the ages of 7 and 18 and is quite well known in the north east of England. It gives young people the opportunity to learn the viol and gives concerts in the North East and abroad. Ensembles like these show that the viol is making a comeback.

A living museum of historical musical instruments was created at the University of Vienna as a center for the revival of the instrument. More than 100 instruments, including approximately 50 historical viola da gambas in playable condition, are the property of this new concept of museum: the Orpheon Foundation Museum of Historical Instruments. All the instruments of this museum are played by the Orpheon Baroque Orchestra, the Orpheon consort, or by musicians who receive an instrument for a permanent loan. The instruments can be seen during temporary exhibitions [1]. They are studied and copied by violin makers, contributing to the extension of the general knowledge we have on the viola da gamba, its forms, and the different techniques used for its manufacture.

Since the late 1980s, numerous instrument makers, including Eric Jensen, Francois Danger, Jan Goorissen, and Jonathan Wilson, have experimented with the design and construction of electric viols. Their range of approaches, from Danger's minimally electrified acoustic/electric Altra line to Eric Jensen's solid-body brace-mounted design, have met with varying degrees of ergonomic and musical success.

In the early 21st century, the Ruby Gamba, a seven-string electric viola da gamba,[24] was developed by Ruby Instruments of Arnhem, the Netherlands. It has 21 tied nylon (adjustable) frets in keeping with the adjustable (tied gut) frets on traditional viols and has an effective playing range of more than six octaves.

The viola da gamba is occasionally confused with the viola, the alto member of the modern violin family and a standard member of both the symphony orchestra and string quartet. In the 15th century, the Italian word "viola" was a generic term used to refer to any bowed instrument, or fiddle. It is important to note that the word "viola" existed in Italy before the vihuela, or first viol, was brought from Spain. In Italy, "viola" was first applied to a braccio precursor to the modern violin, as described by Tinctoris (De inventione et usu musice, c. 1481–3), and then was later used to describe the first Italian viols as well.

Depending on the context, the unmodified "viola da braccio" most regularly denoted either an instrument from the violin family, or specifically the viola (whose specific name was "alto de viola da braccio"). When Monteverdi called simply for "viole da braccio" in "Orfeo", the composer was requesting violas as well as treble and bass instruments.

The full name of the viola namely "alto de viola da braccio" was finally shortened to "viola" in some languages (e.g. English, Italian, Spanish) once viols became less common, while other languages picked some other part of the phrase to designate the instrument, e.g. "alto" in French and "Bratsche" (which comes from the Italian "braccio") in German.

Other instruments which include the word viola in their name but have nothing to do specifically with and are not a member of the viola da gamba family are the viola d'amore and the viola pomposa. Although the baryton doesn't have viola in its name it is sometimes included, wrongly, in the viol family.

The names viola (Italy) and vihuela (Spain) were essentially synonymous and interchangeable. According to viol historian Ian Woodfield, there is little evidence that the vihuela de arco was introduced to Italy before the 1490s. The use of the term "viola" was never used exclusively for viols in the 15th or 16th centuries. In 16th century Italy, both "violas",—the early viols and violins—developed somewhat simultaneously. While the violins such as those of Amati achieved their classic form before the first half of the century, the viol's form would be standardized later in the century by instrument makers in England.

Viola da gamba, viola cum arculo, and vihuela de arco are some (true) alternative names for viols. Both "vihuela" and "viola" were originally used in a fairly generic way, having included even early violins (viola da braccio) under their umbrella. It is common enough (and justifiable) today for modern players of the viola da gamba to call their instruments violas and likewise to call themselves violists. That the "alto violin" eventually became known simply as the "viola" is not without historical context, yet the ambiguity of the name tends to cause some confusion. The violin, or violino, was originally the soprano viola da braccio, or violino da braccio. Due to the popularity of the soprano violin, the entire consort eventually took on the name "violin family".

^van der Straeten, Edmund (1933). The History of the Violin: Its Ancestors and Collateral Instruments from Earliest Times. Cassell and company, ltd.

^The violin and the flute were not considered appropriate for ladies; no longer, in the case of the violin, as in the 17th century, because of its popular origins and association with people who made a living playing music, but because the physical effort required to hold the violin a braccio or to play the flute were not considered lady-like